<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			.container {
				display: flex;
				flex-direction: row;
				justify-content: space-around;/*x轴*/
				align-content: space-between;/*y轴*/
				align-items: center;
				flex-wrap: wrap;
				height: 300px;
				width: 450px;
				background-color: #0000FF;
			}
			
			.d1 {
				width: 100px;
				height: 100px;
				background-color: #000000;
				color: white;
			}
			.btn-group {
				width: 300px;
				display: flex;
				justify-content: space-around;
			}
		</style>
	</head>
	<body>
		<!-- 单根节点 -->
		<div class="container">
			<div class="d1" style="order: 2;align-self: center;">
				1
			</div>
			<div class="d1" style="order: 0;">
				2
			</div>
			<div class="d1" style="order: 1;">
				3
			</div>
			<div class="d1" style="order: 0;">
				4
			</div>
		</div>
		<div class="btn-group">
			<button style="width: 50%;" type="button">注册</button>
			<button style="width: 50%;" type="button">忘记密码</button>
		</div>
	</body>
</html>
